Mobile devices such as cellular phones, personal digital assistants (PDAs) and notebook computers often require authentication when accessing remote databases or networks. Devices are generally authenticated through an Infrastructure Access Point (IAP), such as a base station, which is connected to an authentication server. An authentication request can be transmitted using an Extensible Authentication Protocol (EAP) comprising EAP Over Local Area Network (EAPOL) packets. The authentication process involves several EAPOL packets being transmitted and received, beginning with an EAP Start packet and finishing with either an EAP Success message packet or an EAP Failure message packet. The authentication server stores the authentication credentials of a mobile device (typically called a supplicant) that is being authenticated. Authentication servers also can be connected to other authentication servers to obtain supplicant authentication credentials that are not stored locally.
In prior systems, a centralized procedure is followed where a single IAP handles an authentication process for all supplicants within range of the IAP. Prior systems which adhere to American National Standards Institute/Institute of Electrical and Electronics Engineers (ANSI/IEEE) 802.1X or ANSI/IEEE 802.11i standards utilize such a centralized procedure. Because every supplicant can be authenticated only via the IAP, such a centralized procedure is not practical in multi-hop networks. In the ANSI/IEEE standards, the process of authentication of mobile devices is defined, and the standards discuss a supplicant, an authenticator and an authentication server, where the authentication server authenticates a supplicant using an authenticator. The authentication server trusts the authenticator to forward correct authentication information received from the supplicant to the authentication server. However, the authentication process as defined in the standards requires that the supplicant have a direct communication channel with the authenticator.
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